The present invention relates generally to a security system for inventory, and more particularly to automatically detecting removal of inventory items from an area or areas protected with security sensors (such as radio-frequency identification, or “RFID”, sensors), and in a retail environment, enables shoppers to purchase items directly from shelves or other protected areas.
Theft and shoplifting are problems in many environments. For retail businesses, for example, billions of dollars are lost every year to shoplifting. Employee theft from inventory stored in warehouses is also a serious problem and results in large amounts of lost revenue.
In the retail environment, traditional checkout involves a cashier at the front of the store scanning individual products and completing a purchase transaction for a shopper, all at one time. In recent years, self-checkout point-of-sale (“POS”) stations have been introduced by some retailers. While these self-checkout stations may reduce labor costs for the retailer and reduce waiting time for customers making purchases, new challenges are introduced in preventing theft. Presently, a retailer creates a database of each inventory item offered for sale, where the information stored for each item typically includes the item's Uniform Product Code (“UPC”, sometimes referred to as a “bar code”) or other identifying code, description, price, and weight. When a shopper scans the UPC of an item being purchased using a scanning mechanism at the POS station, the item weight is retrieved from the database. Shoppers are typically directed by the self-checkout POS station to place all purchased items in a particular area of the station, where the collection of scanned items can be weighed. The weight of the collection is then compared against the expected weight of all scanned items (e.g., to determine whether any non-scanned items have been added).
This present approach to self-checkout represents a large amount of time spent at the checkout station. As an additional drawback of this approach, theft is not adequately prevented.
It is known in the art to use RFID scanning of items—either individually or in bulk—at the front of a store, all at one time, to complete a single purchase transaction. For bulk scanning, for example, the entire contents of a shopper's shopping cart may be scanned at a checkout area in the front of a store. However, in actual practice, the radio-frequency energy from the RFID tags tends to be shielded by metal items that may be present in the cart, such as canned goods, aluminum foil, and so forth, and thus this type of bulk scanning sometimes provides incomplete information.